Whilst the present invention has application in the treatment and prevention of many forms of degenerative and/or inflammatory conditions, for the purpose of brevity, the following description shall be limited to discussing its application in the treatment of arthritis, although it should be appreciated that the formulations of the invention could be used to treat other degenerative and/or inflammatory conditions.
Arthritis is a degenerative condition of a joint or joints that is generally associated with pain and inflammation. The two most common forms of arthritis are osteoarthritis and rheumatoid arthritis. Osteoarthritis (OA) is a progressive rheumatic disease characterized by the degeneration of articular cartilage. It is the most common of all rheumatic disorders and is destined to become one of the most prevalent and costly diseases in Western society.
Therapeutic interventions conventionally employed for OA include the use of physiotherapy and antidepressant therapies, patient education and weight control. In addition, drug therapy includes non-opioid analgesics such as paracetamol, non-steroidal anti-inflammatory drugs (NSAIDs), topical analgesics, COX-2 inhibitors, opioid analgesics and intra-articular steroid injection. However, such treatments often prove ineffective in some patients and NSAIDS can have serious adverse effects. For instance, gastrointestinal complications are frequently reported with NSAIDs, with approximately 12,000 hospitalizations and about 2000 deaths attributed to NSAID use in the UK every year. Hence there appears to be a need for drugs with good efficacy and low toxicity in the treatment of OA. Specifically, there is a need for safe and effective drugs for patients who do not respond well to conventional medical therapy. In this respect, many patients are turning increasingly to complementary/alternative medicines (CAM).
The use of CAM by sufferers of rheumatic diseases is highly prevalent and increasing. Arthritis is the sixth most frequently cited health problem treated with CAM in the USA. Individuals who use CAM regularly are more likely to have OA and severe pain. Patients suffering from musculoskeletal problems are likely to be users of herbal treatments. It is therefore important to determine the effectiveness and safety of herbal medicines in the treatment of OA.
A review by Long et al. (Rheumatology, 2001, 40:779-793) found promising evidence in the form of randomized controlled trials of herbal medicines and plant extracts in reducing pain and improving mobility, function and disability in OA. While there is no compelling evidence for significant clinically relevant benefits for CAMs such as Eazmov, Gitadyl or ginger extract, there is weak evidence, in the form of single randomized controlled trials, for mild to moderate relief of symptoms using Reumalex, willow bark, common stinging nettle and the Ayurvedic herbal preparation, Articulin-F. There is also promising evidence for the efficacy of devil's claw and extracts of avocado and soya bean, as well as moderately strong evidence for the efficacy of Phytodolor and capsaicin cream for the relief of OA symptoms.
Topically applied capsaicin is also proposed to exert its action by stimulating a subpopulation of nociceptive pain neurones. Exposure to capsaicin brings about the depletion of substance P, neurones subsequently becoming insensitive to all other exposure, including exposure to capsaicin itself.
The incidence of adverse effects for these herbal medicines appears to be low, and they may offer a much-needed alternative for individuals with long-term chronic OA.
Comfrey root or leaf (in either a crude form or as an extract thereof) has been used in the treatment of OA, however, formulations that include comfrey extracts have only been used to provide temporary relief for the pain associated with OA. For instance, U.S. Pat. No. 5,958,418 describes a herbal composition for the treatment of muscular aches and pains, the composition comprising Aloe vera, capsicum, Golden Seal, the finely chopped bark of the comfrey root and water. U.S. Pat. No. 6,333,056 describes an ingestible herbal based formulation for treatment of horses and dogs to alleviate the symptoms of osteoarthritis, the formulation comprising a mixture of devils claw and comfrey (in a certain embodiment, it may also include a mixture of dandelion, burdock and nettles), as an intimate admixture added to the animals' feed. U.S. Pat. No. 4,059,695 describes a tonic composition in liquid form comprising refined wood vinegar and plant leaf components, such as comfrey leaf, that is said to mitigate arthritis, although experimental evidence is not provided to support that assertion.
The present invention overcomes, or at least alleviates, some of the aforementioned problems of the art by providing a more effective prophylactic or therapeutic treatment for inflammatory and/or degenerative conditions and topical formulations for such use.
The discussion of documents, acts, materials, devices, articles and the like is included in this specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all of these matters formed part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.